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<a class="jxr_linenumber" name="1" href="#1">1</a>   <em class="jxr_comment">/*</em>
<a class="jxr_linenumber" name="2" href="#2">2</a>   <em class="jxr_comment"> * Licensed to the Apache Software Foundation (ASF) under one or more</em>
<a class="jxr_linenumber" name="3" href="#3">3</a>   <em class="jxr_comment"> * contributor license agreements.  See the NOTICE file distributed with</em>
<a class="jxr_linenumber" name="4" href="#4">4</a>   <em class="jxr_comment"> * this work for additional information regarding copyright ownership.</em>
<a class="jxr_linenumber" name="5" href="#5">5</a>   <em class="jxr_comment"> * The ASF licenses this file to You under the Apache License, Version 2.0</em>
<a class="jxr_linenumber" name="6" href="#6">6</a>   <em class="jxr_comment"> * (the "License"); you may not use this file except in compliance with</em>
<a class="jxr_linenumber" name="7" href="#7">7</a>   <em class="jxr_comment"> * the License.  You may obtain a copy of the License at</em>
<a class="jxr_linenumber" name="8" href="#8">8</a>   <em class="jxr_comment"> *</em>
<a class="jxr_linenumber" name="9" href="#9">9</a>   <em class="jxr_comment"> *     <a href="http://www.apache.org/licenses/LICENSE-2.0" target="alexandria_uri">http://www.apache.org/licenses/LICENSE-2.0</a></em>
<a class="jxr_linenumber" name="10" href="#10">10</a>  <em class="jxr_comment"> *</em>
<a class="jxr_linenumber" name="11" href="#11">11</a>  <em class="jxr_comment"> * Unless required by applicable law or agreed to in writing, software</em>
<a class="jxr_linenumber" name="12" href="#12">12</a>  <em class="jxr_comment"> * distributed under the License is distributed on an "AS IS" BASIS,</em>
<a class="jxr_linenumber" name="13" href="#13">13</a>  <em class="jxr_comment"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</em>
<a class="jxr_linenumber" name="14" href="#14">14</a>  <em class="jxr_comment"> * See the License for the specific language governing permissions and</em>
<a class="jxr_linenumber" name="15" href="#15">15</a>  <em class="jxr_comment"> * limitations under the License.</em>
<a class="jxr_linenumber" name="16" href="#16">16</a>  <em class="jxr_comment"> */</em>
<a class="jxr_linenumber" name="17" href="#17">17</a>  <strong class="jxr_keyword">package</strong> org.apache.commons.configuration;
<a class="jxr_linenumber" name="18" href="#18">18</a>  
<a class="jxr_linenumber" name="19" href="#19">19</a>  <strong class="jxr_keyword">import</strong> java.util.ArrayList;
<a class="jxr_linenumber" name="20" href="#20">20</a>  <strong class="jxr_keyword">import</strong> java.util.Collections;
<a class="jxr_linenumber" name="21" href="#21">21</a>  <strong class="jxr_keyword">import</strong> java.util.List;
<a class="jxr_linenumber" name="22" href="#22">22</a>  
<a class="jxr_linenumber" name="23" href="#23">23</a>  <strong class="jxr_keyword">import</strong> org.apache.commons.configuration.interpol.ConfigurationInterpolator;
<a class="jxr_linenumber" name="24" href="#24">24</a>  <strong class="jxr_keyword">import</strong> org.apache.commons.configuration.reloading.Reloadable;
<a class="jxr_linenumber" name="25" href="#25">25</a>  <strong class="jxr_keyword">import</strong> org.apache.commons.configuration.tree.ConfigurationNode;
<a class="jxr_linenumber" name="26" href="#26">26</a>  
<a class="jxr_linenumber" name="27" href="#27">27</a>  <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="28" href="#28">28</a>  <em class="jxr_javadoccomment"> * &lt;p&gt;</em>
<a class="jxr_linenumber" name="29" href="#29">29</a>  <em class="jxr_javadoccomment"> * A specialized hierarchical configuration class that wraps a single node of</em>
<a class="jxr_linenumber" name="30" href="#30">30</a>  <em class="jxr_javadoccomment"> * its parent configuration.</em>
<a class="jxr_linenumber" name="31" href="#31">31</a>  <em class="jxr_javadoccomment"> * &lt;/p&gt;</em>
<a class="jxr_linenumber" name="32" href="#32">32</a>  <em class="jxr_javadoccomment"> * &lt;p&gt;</em>
<a class="jxr_linenumber" name="33" href="#33">33</a>  <em class="jxr_javadoccomment"> * Configurations of this type are initialized with a parent configuration and a</em>
<a class="jxr_linenumber" name="34" href="#34">34</a>  <em class="jxr_javadoccomment"> * configuration node of this configuration. This node becomes the root node of</em>
<a class="jxr_linenumber" name="35" href="#35">35</a>  <em class="jxr_javadoccomment"> * the subnode configuration. All property accessor methods are evaluated</em>
<a class="jxr_linenumber" name="36" href="#36">36</a>  <em class="jxr_javadoccomment"> * relative to this root node. A good use case for a</em>
<a class="jxr_linenumber" name="37" href="#37">37</a>  <em class="jxr_javadoccomment"> * {@code SubnodeConfiguration} is when multiple properties from a</em>
<a class="jxr_linenumber" name="38" href="#38">38</a>  <em class="jxr_javadoccomment"> * specific sub tree of the whole configuration need to be accessed. Then a</em>
<a class="jxr_linenumber" name="39" href="#39">39</a>  <em class="jxr_javadoccomment"> * {@code SubnodeConfiguration} can be created with the parent node of</em>
<a class="jxr_linenumber" name="40" href="#40">40</a>  <em class="jxr_javadoccomment"> * the affected sub tree as root node. This allows for simpler property keys and</em>
<a class="jxr_linenumber" name="41" href="#41">41</a>  <em class="jxr_javadoccomment"> * is also more efficient.</em>
<a class="jxr_linenumber" name="42" href="#42">42</a>  <em class="jxr_javadoccomment"> * &lt;/p&gt;</em>
<a class="jxr_linenumber" name="43" href="#43">43</a>  <em class="jxr_javadoccomment"> * &lt;p&gt;</em>
<a class="jxr_linenumber" name="44" href="#44">44</a>  <em class="jxr_javadoccomment"> * A subnode configuration and its parent configuration operate on the same</em>
<a class="jxr_linenumber" name="45" href="#45">45</a>  <em class="jxr_javadoccomment"> * hierarchy of configuration nodes. So if modifications are performed at the</em>
<a class="jxr_linenumber" name="46" href="#46">46</a>  <em class="jxr_javadoccomment"> * subnode configuration, these changes are immediately visible in the parent</em>
<a class="jxr_linenumber" name="47" href="#47">47</a>  <em class="jxr_javadoccomment"> * configuration. Analogously will updates of the parent configuration affect</em>
<a class="jxr_linenumber" name="48" href="#48">48</a>  <em class="jxr_javadoccomment"> * the subnode configuration if the sub tree spanned by the subnode</em>
<a class="jxr_linenumber" name="49" href="#49">49</a>  <em class="jxr_javadoccomment"> * configuration's root node is involved.</em>
<a class="jxr_linenumber" name="50" href="#50">50</a>  <em class="jxr_javadoccomment"> * &lt;/p&gt;</em>
<a class="jxr_linenumber" name="51" href="#51">51</a>  <em class="jxr_javadoccomment"> * &lt;p&gt;</em>
<a class="jxr_linenumber" name="52" href="#52">52</a>  <em class="jxr_javadoccomment"> * There are however changes at the parent configuration, which cause the</em>
<a class="jxr_linenumber" name="53" href="#53">53</a>  <em class="jxr_javadoccomment"> * subnode configuration to become detached. An example for such a change is a</em>
<a class="jxr_linenumber" name="54" href="#54">54</a>  <em class="jxr_javadoccomment"> * reload operation of a file-based configuration, which replaces all nodes of</em>
<a class="jxr_linenumber" name="55" href="#55">55</a>  <em class="jxr_javadoccomment"> * the parent configuration. The subnode configuration per default still</em>
<a class="jxr_linenumber" name="56" href="#56">56</a>  <em class="jxr_javadoccomment"> * references the old nodes. Another example are list structures: a subnode</em>
<a class="jxr_linenumber" name="57" href="#57">57</a>  <em class="jxr_javadoccomment"> * configuration can be created to point on the &lt;em&gt;i&lt;/em&gt;th element of the</em>
<a class="jxr_linenumber" name="58" href="#58">58</a>  <em class="jxr_javadoccomment"> * list. Now list elements can be added or removed, so that the list elements'</em>
<a class="jxr_linenumber" name="59" href="#59">59</a>  <em class="jxr_javadoccomment"> * indices change. In such a scenario the subnode configuration would always</em>
<a class="jxr_linenumber" name="60" href="#60">60</a>  <em class="jxr_javadoccomment"> * point to the same list element, regardless of its current index.</em>
<a class="jxr_linenumber" name="61" href="#61">61</a>  <em class="jxr_javadoccomment"> * &lt;/p&gt;</em>
<a class="jxr_linenumber" name="62" href="#62">62</a>  <em class="jxr_javadoccomment"> * &lt;p&gt;</em>
<a class="jxr_linenumber" name="63" href="#63">63</a>  <em class="jxr_javadoccomment"> * To solve these problems and make a subnode configuration aware of</em>
<a class="jxr_linenumber" name="64" href="#64">64</a>  <em class="jxr_javadoccomment"> * such structural changes of its parent, it is possible to associate a</em>
<a class="jxr_linenumber" name="65" href="#65">65</a>  <em class="jxr_javadoccomment"> * subnode configuration with a configuration key. This can be done by calling</em>
<a class="jxr_linenumber" name="66" href="#66">66</a>  <em class="jxr_javadoccomment"> * the {@code setSubnodeKey()} method. If here a key is set, the subnode</em>
<a class="jxr_linenumber" name="67" href="#67">67</a>  <em class="jxr_javadoccomment"> * configuration will evaluate it on each access, thus ensuring that it is</em>
<a class="jxr_linenumber" name="68" href="#68">68</a>  <em class="jxr_javadoccomment"> * always in sync with its parent. In this mode the subnode configuration really</em>
<a class="jxr_linenumber" name="69" href="#69">69</a>  <em class="jxr_javadoccomment"> * behaves like a live-view on its parent. The price for this is a decreased</em>
<a class="jxr_linenumber" name="70" href="#70">70</a>  <em class="jxr_javadoccomment"> * performance because now an additional evaluation has to be performed on each</em>
<a class="jxr_linenumber" name="71" href="#71">71</a>  <em class="jxr_javadoccomment"> * property access. So this mode should only be used if necessary; if for</em>
<a class="jxr_linenumber" name="72" href="#72">72</a>  <em class="jxr_javadoccomment"> * instance a subnode configuration is only used for a temporary convenient</em>
<a class="jxr_linenumber" name="73" href="#73">73</a>  <em class="jxr_javadoccomment"> * access to a complex configuration, there is no need to make it aware for</em>
<a class="jxr_linenumber" name="74" href="#74">74</a>  <em class="jxr_javadoccomment"> * structural changes of its parent. If a subnode configuration is created</em>
<a class="jxr_linenumber" name="75" href="#75">75</a>  <em class="jxr_javadoccomment"> * using the {@link HierarchicalConfiguration#configurationAt(String, boolean)</em>
<a class="jxr_linenumber" name="76" href="#76">76</a>  <em class="jxr_javadoccomment"> * configurationAt()} method of {@code HierarchicalConfiguration}</em>
<a class="jxr_linenumber" name="77" href="#77">77</a>  <em class="jxr_javadoccomment"> * (which should be the preferred way), with an additional boolean parameter it</em>
<a class="jxr_linenumber" name="78" href="#78">78</a>  <em class="jxr_javadoccomment"> * can be specified whether the resulting subnode configuration should be</em>
<a class="jxr_linenumber" name="79" href="#79">79</a>  <em class="jxr_javadoccomment"> * aware of structural changes or not. Then the configuration key will be</em>
<a class="jxr_linenumber" name="80" href="#80">80</a>  <em class="jxr_javadoccomment"> * automatically set.</em>
<a class="jxr_linenumber" name="81" href="#81">81</a>  <em class="jxr_javadoccomment"> * &lt;/p&gt;</em>
<a class="jxr_linenumber" name="82" href="#82">82</a>  <em class="jxr_javadoccomment"> * &lt;p&gt;</em>
<a class="jxr_linenumber" name="83" href="#83">83</a>  <em class="jxr_javadoccomment"> * &lt;em&gt;Note:&lt;/em&gt; At the moment support for creating a subnode configuration</em>
<a class="jxr_linenumber" name="84" href="#84">84</a>  <em class="jxr_javadoccomment"> * that is aware of structural changes of its parent from another subnode</em>
<a class="jxr_linenumber" name="85" href="#85">85</a>  <em class="jxr_javadoccomment"> * configuration (a "sub subnode configuration") is limited. This only works if</em>
<a class="jxr_linenumber" name="86" href="#86">86</a>  <em class="jxr_javadoccomment"> * &lt;ol&gt;&lt;li&gt;the subnode configuration that serves as the parent for the new</em>
<a class="jxr_linenumber" name="87" href="#87">87</a>  <em class="jxr_javadoccomment"> * subnode configuration is itself associated with a configuration key and&lt;/li&gt;</em>
<a class="jxr_linenumber" name="88" href="#88">88</a>  <em class="jxr_javadoccomment"> * &lt;li&gt;the key passed in to create the new subnode configuration is not too</em>
<a class="jxr_linenumber" name="89" href="#89">89</a>  <em class="jxr_javadoccomment"> * complex (if configuration keys are used that contain indices, a corresponding</em>
<a class="jxr_linenumber" name="90" href="#90">90</a>  <em class="jxr_javadoccomment"> * key that is valid from the parent configuration's point of view cannot be</em>
<a class="jxr_linenumber" name="91" href="#91">91</a>  <em class="jxr_javadoccomment"> * constructed).&lt;/li&gt;&lt;/ol&gt;</em>
<a class="jxr_linenumber" name="92" href="#92">92</a>  <em class="jxr_javadoccomment"> * &lt;/p&gt;</em>
<a class="jxr_linenumber" name="93" href="#93">93</a>  <em class="jxr_javadoccomment"> * &lt;p&gt;</em>
<a class="jxr_linenumber" name="94" href="#94">94</a>  <em class="jxr_javadoccomment"> * When a subnode configuration is created, it inherits the settings of its</em>
<a class="jxr_linenumber" name="95" href="#95">95</a>  <em class="jxr_javadoccomment"> * parent configuration, e.g. some flags like the</em>
<a class="jxr_linenumber" name="96" href="#96">96</a>  <em class="jxr_javadoccomment"> * {@code throwExceptionOnMissing} flag or the settings for handling list</em>
<a class="jxr_linenumber" name="97" href="#97">97</a>  <em class="jxr_javadoccomment"> * delimiters) or the expression engine. If these settings are changed later in</em>
<a class="jxr_linenumber" name="98" href="#98">98</a>  <em class="jxr_javadoccomment"> * either the subnode or the parent configuration, the changes are not visible</em>
<a class="jxr_linenumber" name="99" href="#99">99</a>  <em class="jxr_javadoccomment"> * for each other. So you could create a subnode configuration, change its</em>
<a class="jxr_linenumber" name="100" href="#100">100</a> <em class="jxr_javadoccomment"> * expression engine without affecting the parent configuration.</em>
<a class="jxr_linenumber" name="101" href="#101">101</a> <em class="jxr_javadoccomment"> * &lt;/p&gt;</em>
<a class="jxr_linenumber" name="102" href="#102">102</a> <em class="jxr_javadoccomment"> * &lt;p&gt;</em>
<a class="jxr_linenumber" name="103" href="#103">103</a> <em class="jxr_javadoccomment"> * From its purpose this class is quite similar to</em>
<a class="jxr_linenumber" name="104" href="#104">104</a> <em class="jxr_javadoccomment"> * {@link SubsetConfiguration}. The difference is that a subset</em>
<a class="jxr_linenumber" name="105" href="#105">105</a> <em class="jxr_javadoccomment"> * configuration of a hierarchical configuration may combine multiple</em>
<a class="jxr_linenumber" name="106" href="#106">106</a> <em class="jxr_javadoccomment"> * configuration nodes from different sub trees of the configuration, while all</em>
<a class="jxr_linenumber" name="107" href="#107">107</a> <em class="jxr_javadoccomment"> * nodes in a subnode configuration belong to the same sub tree. If an</em>
<a class="jxr_linenumber" name="108" href="#108">108</a> <em class="jxr_javadoccomment"> * application can live with this limitation, it is recommended to use this</em>
<a class="jxr_linenumber" name="109" href="#109">109</a> <em class="jxr_javadoccomment"> * class instead of {@code SubsetConfiguration} because creating a subset</em>
<a class="jxr_linenumber" name="110" href="#110">110</a> <em class="jxr_javadoccomment"> * configuration is more expensive than creating a subnode configuration.</em>
<a class="jxr_linenumber" name="111" href="#111">111</a> <em class="jxr_javadoccomment"> * &lt;/p&gt;</em>
<a class="jxr_linenumber" name="112" href="#112">112</a> <em class="jxr_javadoccomment"> *</em>
<a class="jxr_linenumber" name="113" href="#113">113</a> <em class="jxr_javadoccomment"> * @since 1.3</em>
<a class="jxr_linenumber" name="114" href="#114">114</a> <em class="jxr_javadoccomment"> * @author &lt;a</em>
<a class="jxr_linenumber" name="115" href="#115">115</a> <em class="jxr_javadoccomment"> * href="<a href="http://commons.apache.org/configuration/team-list.html" target="alexandria_uri">http://commons.apache.org/configuration/team-list.html</a>"&gt;Commons</em>
<a class="jxr_linenumber" name="116" href="#116">116</a> <em class="jxr_javadoccomment"> * Configuration team&lt;/a&gt;</em>
<a class="jxr_linenumber" name="117" href="#117">117</a> <em class="jxr_javadoccomment"> * @version $Id: SubnodeConfiguration.java 1210178 2011-12-04 18:58:51Z oheger $</em>
<a class="jxr_linenumber" name="118" href="#118">118</a> <em class="jxr_javadoccomment"> */</em>
<a class="jxr_linenumber" name="119" href="#119">119</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">class</strong> <a href="../../../../org/apache/commons/configuration/SubnodeConfiguration.html">SubnodeConfiguration</a> <strong class="jxr_keyword">extends</strong> <a href="../../../../org/apache/commons/configuration/HierarchicalReloadableConfiguration.html">HierarchicalReloadableConfiguration</a>
<a class="jxr_linenumber" name="120" href="#120">120</a> {
<a class="jxr_linenumber" name="121" href="#121">121</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="122" href="#122">122</a> <em class="jxr_javadoccomment">     * The serial version UID.</em>
<a class="jxr_linenumber" name="123" href="#123">123</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="124" href="#124">124</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">long</strong> serialVersionUID = 3105734147019386480L;
<a class="jxr_linenumber" name="125" href="#125">125</a> 
<a class="jxr_linenumber" name="126" href="#126">126</a>     <em class="jxr_javadoccomment">/**</em><em class="jxr_javadoccomment"> Stores the parent configuration. */</em>
<a class="jxr_linenumber" name="127" href="#127">127</a>     <strong class="jxr_keyword">private</strong> <a href="../../../../org/apache/commons/configuration/HierarchicalConfiguration.html">HierarchicalConfiguration</a> parent;
<a class="jxr_linenumber" name="128" href="#128">128</a> 
<a class="jxr_linenumber" name="129" href="#129">129</a>     <em class="jxr_javadoccomment">/**</em><em class="jxr_javadoccomment"> Stores the key that was used to construct this configuration.*/</em>
<a class="jxr_linenumber" name="130" href="#130">130</a>     <strong class="jxr_keyword">private</strong> String subnodeKey;
<a class="jxr_linenumber" name="131" href="#131">131</a> 
<a class="jxr_linenumber" name="132" href="#132">132</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="133" href="#133">133</a> <em class="jxr_javadoccomment">     * Creates a new instance of {@code SubnodeConfiguration} and</em>
<a class="jxr_linenumber" name="134" href="#134">134</a> <em class="jxr_javadoccomment">     * initializes it with the parent configuration and the new root node.</em>
<a class="jxr_linenumber" name="135" href="#135">135</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="136" href="#136">136</a> <em class="jxr_javadoccomment">     * @param parent the parent configuration</em>
<a class="jxr_linenumber" name="137" href="#137">137</a> <em class="jxr_javadoccomment">     * @param root the root node of this subnode configuration</em>
<a class="jxr_linenumber" name="138" href="#138">138</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="139" href="#139">139</a>     <strong class="jxr_keyword">public</strong> <a href="../../../../org/apache/commons/configuration/SubnodeConfiguration.html">SubnodeConfiguration</a>(<a href="../../../../org/apache/commons/configuration/HierarchicalConfiguration.html">HierarchicalConfiguration</a> parent, <a href="../../../../org/apache/commons/configuration/tree/ConfigurationNode.html">ConfigurationNode</a> root)
<a class="jxr_linenumber" name="140" href="#140">140</a>     {
<a class="jxr_linenumber" name="141" href="#141">141</a>         <strong class="jxr_keyword">super</strong>(parent instanceof <a href="../../../../org/apache/commons/configuration/reloading/Reloadable.html">Reloadable</a> ? ((Reloadable) parent).getReloadLock() : <strong class="jxr_keyword">null</strong>);
<a class="jxr_linenumber" name="142" href="#142">142</a>         <strong class="jxr_keyword">if</strong> (parent == <strong class="jxr_keyword">null</strong>)
<a class="jxr_linenumber" name="143" href="#143">143</a>         {
<a class="jxr_linenumber" name="144" href="#144">144</a>             <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> IllegalArgumentException(
<a class="jxr_linenumber" name="145" href="#145">145</a>                     <span class="jxr_string">"Parent configuration must not be null!"</span>);
<a class="jxr_linenumber" name="146" href="#146">146</a>         }
<a class="jxr_linenumber" name="147" href="#147">147</a>         <strong class="jxr_keyword">if</strong> (root == <strong class="jxr_keyword">null</strong>)
<a class="jxr_linenumber" name="148" href="#148">148</a>         {
<a class="jxr_linenumber" name="149" href="#149">149</a>             <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> IllegalArgumentException(<span class="jxr_string">"Root node must not be null!"</span>);
<a class="jxr_linenumber" name="150" href="#150">150</a>         }
<a class="jxr_linenumber" name="151" href="#151">151</a> 
<a class="jxr_linenumber" name="152" href="#152">152</a>         setRootNode(root);
<a class="jxr_linenumber" name="153" href="#153">153</a>         <strong class="jxr_keyword">this</strong>.parent = parent;
<a class="jxr_linenumber" name="154" href="#154">154</a>         initFromParent(parent);
<a class="jxr_linenumber" name="155" href="#155">155</a>     }
<a class="jxr_linenumber" name="156" href="#156">156</a> 
<a class="jxr_linenumber" name="157" href="#157">157</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="158" href="#158">158</a> <em class="jxr_javadoccomment">     * Returns the parent configuration of this subnode configuration.</em>
<a class="jxr_linenumber" name="159" href="#159">159</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="160" href="#160">160</a> <em class="jxr_javadoccomment">     * @return the parent configuration</em>
<a class="jxr_linenumber" name="161" href="#161">161</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="162" href="#162">162</a>     <strong class="jxr_keyword">public</strong> <a href="../../../../org/apache/commons/configuration/HierarchicalConfiguration.html">HierarchicalConfiguration</a> getParent()
<a class="jxr_linenumber" name="163" href="#163">163</a>     {
<a class="jxr_linenumber" name="164" href="#164">164</a>         <strong class="jxr_keyword">return</strong> parent;
<a class="jxr_linenumber" name="165" href="#165">165</a>     }
<a class="jxr_linenumber" name="166" href="#166">166</a> 
<a class="jxr_linenumber" name="167" href="#167">167</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="168" href="#168">168</a> <em class="jxr_javadoccomment">     * Returns the key that was used to construct this configuration. If here a</em>
<a class="jxr_linenumber" name="169" href="#169">169</a> <em class="jxr_javadoccomment">     * non-&lt;b&gt;null&lt;/b&gt; value is returned, the subnode configuration will</em>
<a class="jxr_linenumber" name="170" href="#170">170</a> <em class="jxr_javadoccomment">     * always check its parent for structural changes and reconstruct itself if</em>
<a class="jxr_linenumber" name="171" href="#171">171</a> <em class="jxr_javadoccomment">     * necessary.</em>
<a class="jxr_linenumber" name="172" href="#172">172</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="173" href="#173">173</a> <em class="jxr_javadoccomment">     * @return the key for selecting this configuration's root node</em>
<a class="jxr_linenumber" name="174" href="#174">174</a> <em class="jxr_javadoccomment">     * @since 1.5</em>
<a class="jxr_linenumber" name="175" href="#175">175</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="176" href="#176">176</a>     <strong class="jxr_keyword">public</strong> String getSubnodeKey()
<a class="jxr_linenumber" name="177" href="#177">177</a>     {
<a class="jxr_linenumber" name="178" href="#178">178</a>         <strong class="jxr_keyword">return</strong> subnodeKey;
<a class="jxr_linenumber" name="179" href="#179">179</a>     }
<a class="jxr_linenumber" name="180" href="#180">180</a> 
<a class="jxr_linenumber" name="181" href="#181">181</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="182" href="#182">182</a> <em class="jxr_javadoccomment">     * Sets the key to the root node of this subnode configuration. If here a</em>
<a class="jxr_linenumber" name="183" href="#183">183</a> <em class="jxr_javadoccomment">     * key is set, the subnode configuration will behave like a live-view on its</em>
<a class="jxr_linenumber" name="184" href="#184">184</a> <em class="jxr_javadoccomment">     * parent for this key. See the class comment for more details.</em>
<a class="jxr_linenumber" name="185" href="#185">185</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="186" href="#186">186</a> <em class="jxr_javadoccomment">     * @param subnodeKey the key used to construct this configuration</em>
<a class="jxr_linenumber" name="187" href="#187">187</a> <em class="jxr_javadoccomment">     * @since 1.5</em>
<a class="jxr_linenumber" name="188" href="#188">188</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="189" href="#189">189</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">void</strong> setSubnodeKey(String subnodeKey)
<a class="jxr_linenumber" name="190" href="#190">190</a>     {
<a class="jxr_linenumber" name="191" href="#191">191</a>         <strong class="jxr_keyword">this</strong>.subnodeKey = subnodeKey;
<a class="jxr_linenumber" name="192" href="#192">192</a>     }
<a class="jxr_linenumber" name="193" href="#193">193</a> 
<a class="jxr_linenumber" name="194" href="#194">194</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="195" href="#195">195</a> <em class="jxr_javadoccomment">     * Returns the root node for this configuration. If a subnode key is set,</em>
<a class="jxr_linenumber" name="196" href="#196">196</a> <em class="jxr_javadoccomment">     * this implementation re-evaluates this key to find out if this subnode</em>
<a class="jxr_linenumber" name="197" href="#197">197</a> <em class="jxr_javadoccomment">     * configuration needs to be reconstructed. This ensures that the subnode</em>
<a class="jxr_linenumber" name="198" href="#198">198</a> <em class="jxr_javadoccomment">     * configuration is always synchronized with its parent configuration.</em>
<a class="jxr_linenumber" name="199" href="#199">199</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="200" href="#200">200</a> <em class="jxr_javadoccomment">     * @return the root node of this configuration</em>
<a class="jxr_linenumber" name="201" href="#201">201</a> <em class="jxr_javadoccomment">     * @since 1.5</em>
<a class="jxr_linenumber" name="202" href="#202">202</a> <em class="jxr_javadoccomment">     * @see #setSubnodeKey(String)</em>
<a class="jxr_linenumber" name="203" href="#203">203</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="204" href="#204">204</a>     @Override
<a class="jxr_linenumber" name="205" href="#205">205</a>     <strong class="jxr_keyword">public</strong> <a href="../../../../org/apache/commons/configuration/tree/ConfigurationNode.html">ConfigurationNode</a> getRootNode()
<a class="jxr_linenumber" name="206" href="#206">206</a>     {
<a class="jxr_linenumber" name="207" href="#207">207</a>         <strong class="jxr_keyword">if</strong> (getSubnodeKey() != <strong class="jxr_keyword">null</strong>)
<a class="jxr_linenumber" name="208" href="#208">208</a>         {
<a class="jxr_linenumber" name="209" href="#209">209</a>             <strong class="jxr_keyword">try</strong>
<a class="jxr_linenumber" name="210" href="#210">210</a>             {
<a class="jxr_linenumber" name="211" href="#211">211</a>                 List&lt;ConfigurationNode&gt; nodes = getParent().fetchNodeList(getSubnodeKey());
<a class="jxr_linenumber" name="212" href="#212">212</a>                 <strong class="jxr_keyword">if</strong> (nodes.size() != 1)
<a class="jxr_linenumber" name="213" href="#213">213</a>                 {
<a class="jxr_linenumber" name="214" href="#214">214</a>                     <em class="jxr_comment">// key is invalid, so detach this subnode configuration</em>
<a class="jxr_linenumber" name="215" href="#215">215</a>                     setSubnodeKey(<strong class="jxr_keyword">null</strong>);
<a class="jxr_linenumber" name="216" href="#216">216</a>                 }
<a class="jxr_linenumber" name="217" href="#217">217</a>                 <strong class="jxr_keyword">else</strong>
<a class="jxr_linenumber" name="218" href="#218">218</a>                 {
<a class="jxr_linenumber" name="219" href="#219">219</a>                     <a href="../../../../org/apache/commons/configuration/tree/ConfigurationNode.html">ConfigurationNode</a> currentRoot = nodes.get(0);
<a class="jxr_linenumber" name="220" href="#220">220</a>                     <strong class="jxr_keyword">if</strong> (currentRoot != <strong class="jxr_keyword">super</strong>.getRootNode())
<a class="jxr_linenumber" name="221" href="#221">221</a>                     {
<a class="jxr_linenumber" name="222" href="#222">222</a>                         <em class="jxr_comment">// the root node was changed due to a change of the</em>
<a class="jxr_linenumber" name="223" href="#223">223</a>                         <em class="jxr_comment">// parent</em>
<a class="jxr_linenumber" name="224" href="#224">224</a>                         fireEvent(EVENT_SUBNODE_CHANGED, <strong class="jxr_keyword">null</strong>, <strong class="jxr_keyword">null</strong>, <strong class="jxr_keyword">true</strong>);
<a class="jxr_linenumber" name="225" href="#225">225</a>                         setRootNode(currentRoot);
<a class="jxr_linenumber" name="226" href="#226">226</a>                         fireEvent(EVENT_SUBNODE_CHANGED, <strong class="jxr_keyword">null</strong>, <strong class="jxr_keyword">null</strong>, false);
<a class="jxr_linenumber" name="227" href="#227">227</a>                     }
<a class="jxr_linenumber" name="228" href="#228">228</a>                     <strong class="jxr_keyword">return</strong> currentRoot;
<a class="jxr_linenumber" name="229" href="#229">229</a>                 }
<a class="jxr_linenumber" name="230" href="#230">230</a>             }
<a class="jxr_linenumber" name="231" href="#231">231</a>             <strong class="jxr_keyword">catch</strong> (Exception ex)
<a class="jxr_linenumber" name="232" href="#232">232</a>             {
<a class="jxr_linenumber" name="233" href="#233">233</a>                 <em class="jxr_comment">// Evaluation of the key caused an exception. Probably the</em>
<a class="jxr_linenumber" name="234" href="#234">234</a>                 <em class="jxr_comment">// expression engine has changed on the parent. Detach this</em>
<a class="jxr_linenumber" name="235" href="#235">235</a>                 <em class="jxr_comment">// configuration, there is not much we can do about this.</em>
<a class="jxr_linenumber" name="236" href="#236">236</a>                 setSubnodeKey(<strong class="jxr_keyword">null</strong>);
<a class="jxr_linenumber" name="237" href="#237">237</a>             }
<a class="jxr_linenumber" name="238" href="#238">238</a>         }
<a class="jxr_linenumber" name="239" href="#239">239</a> 
<a class="jxr_linenumber" name="240" href="#240">240</a>         <strong class="jxr_keyword">return</strong> <strong class="jxr_keyword">super</strong>.getRootNode(); <em class="jxr_comment">// use stored root node</em>
<a class="jxr_linenumber" name="241" href="#241">241</a>     }
<a class="jxr_linenumber" name="242" href="#242">242</a> 
<a class="jxr_linenumber" name="243" href="#243">243</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="244" href="#244">244</a> <em class="jxr_javadoccomment">     * Returns a hierarchical configuration object for the given sub node.</em>
<a class="jxr_linenumber" name="245" href="#245">245</a> <em class="jxr_javadoccomment">     * This implementation will ensure that the returned</em>
<a class="jxr_linenumber" name="246" href="#246">246</a> <em class="jxr_javadoccomment">     * {@code SubnodeConfiguration} object will have the same parent than</em>
<a class="jxr_linenumber" name="247" href="#247">247</a> <em class="jxr_javadoccomment">     * this object.</em>
<a class="jxr_linenumber" name="248" href="#248">248</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="249" href="#249">249</a> <em class="jxr_javadoccomment">     * @param node the sub node, for which the configuration is to be created</em>
<a class="jxr_linenumber" name="250" href="#250">250</a> <em class="jxr_javadoccomment">     * @return a hierarchical configuration for this sub node</em>
<a class="jxr_linenumber" name="251" href="#251">251</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="252" href="#252">252</a>     @Override
<a class="jxr_linenumber" name="253" href="#253">253</a>     <strong class="jxr_keyword">protected</strong> <a href="../../../../org/apache/commons/configuration/SubnodeConfiguration.html">SubnodeConfiguration</a> createSubnodeConfiguration(<a href="../../../../org/apache/commons/configuration/tree/ConfigurationNode.html">ConfigurationNode</a> node)
<a class="jxr_linenumber" name="254" href="#254">254</a>     {
<a class="jxr_linenumber" name="255" href="#255">255</a>         <a href="../../../../org/apache/commons/configuration/SubnodeConfiguration.html">SubnodeConfiguration</a> result = <strong class="jxr_keyword">new</strong> <a href="../../../../org/apache/commons/configuration/SubnodeConfiguration.html">SubnodeConfiguration</a>(getParent(), node);
<a class="jxr_linenumber" name="256" href="#256">256</a>         getParent().registerSubnodeConfiguration(result);
<a class="jxr_linenumber" name="257" href="#257">257</a>         <strong class="jxr_keyword">return</strong> result;
<a class="jxr_linenumber" name="258" href="#258">258</a>     }
<a class="jxr_linenumber" name="259" href="#259">259</a> 
<a class="jxr_linenumber" name="260" href="#260">260</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="261" href="#261">261</a> <em class="jxr_javadoccomment">     * Returns a hierarchical configuration object for the given sub node that</em>
<a class="jxr_linenumber" name="262" href="#262">262</a> <em class="jxr_javadoccomment">     * is aware of structural changes of its parent. Works like the method with</em>
<a class="jxr_linenumber" name="263" href="#263">263</a> <em class="jxr_javadoccomment">     * the same name, but also sets the subnode key for the new subnode</em>
<a class="jxr_linenumber" name="264" href="#264">264</a> <em class="jxr_javadoccomment">     * configuration, so it can check whether the parent has been changed. This</em>
<a class="jxr_linenumber" name="265" href="#265">265</a> <em class="jxr_javadoccomment">     * only works if this subnode configuration has itself a valid subnode key.</em>
<a class="jxr_linenumber" name="266" href="#266">266</a> <em class="jxr_javadoccomment">     * So if a subnode configuration that should be aware of structural changes</em>
<a class="jxr_linenumber" name="267" href="#267">267</a> <em class="jxr_javadoccomment">     * is created from an already existing subnode configuration, this subnode</em>
<a class="jxr_linenumber" name="268" href="#268">268</a> <em class="jxr_javadoccomment">     * configuration must also be aware of such changes.</em>
<a class="jxr_linenumber" name="269" href="#269">269</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="270" href="#270">270</a> <em class="jxr_javadoccomment">     * @param node the sub node, for which the configuration is to be created</em>
<a class="jxr_linenumber" name="271" href="#271">271</a> <em class="jxr_javadoccomment">     * @param subnodeKey the construction key</em>
<a class="jxr_linenumber" name="272" href="#272">272</a> <em class="jxr_javadoccomment">     * @return a hierarchical configuration for this sub node</em>
<a class="jxr_linenumber" name="273" href="#273">273</a> <em class="jxr_javadoccomment">     * @since 1.5</em>
<a class="jxr_linenumber" name="274" href="#274">274</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="275" href="#275">275</a>     @Override
<a class="jxr_linenumber" name="276" href="#276">276</a>     <strong class="jxr_keyword">protected</strong> <a href="../../../../org/apache/commons/configuration/SubnodeConfiguration.html">SubnodeConfiguration</a> createSubnodeConfiguration(
<a class="jxr_linenumber" name="277" href="#277">277</a>             <a href="../../../../org/apache/commons/configuration/tree/ConfigurationNode.html">ConfigurationNode</a> node, String subnodeKey)
<a class="jxr_linenumber" name="278" href="#278">278</a>     {
<a class="jxr_linenumber" name="279" href="#279">279</a>         <a href="../../../../org/apache/commons/configuration/SubnodeConfiguration.html">SubnodeConfiguration</a> result = createSubnodeConfiguration(node);
<a class="jxr_linenumber" name="280" href="#280">280</a> 
<a class="jxr_linenumber" name="281" href="#281">281</a>         <strong class="jxr_keyword">if</strong> (getSubnodeKey() != <strong class="jxr_keyword">null</strong>)
<a class="jxr_linenumber" name="282" href="#282">282</a>         {
<a class="jxr_linenumber" name="283" href="#283">283</a>             <em class="jxr_comment">// construct the correct subnode key</em>
<a class="jxr_linenumber" name="284" href="#284">284</a>             <em class="jxr_comment">// determine path to root node</em>
<a class="jxr_linenumber" name="285" href="#285">285</a>             List&lt;ConfigurationNode&gt; lstPathToRoot = <strong class="jxr_keyword">new</strong> ArrayList&lt;ConfigurationNode&gt;();
<a class="jxr_linenumber" name="286" href="#286">286</a>             <a href="../../../../org/apache/commons/configuration/tree/ConfigurationNode.html">ConfigurationNode</a> top = <strong class="jxr_keyword">super</strong>.getRootNode();
<a class="jxr_linenumber" name="287" href="#287">287</a>             <a href="../../../../org/apache/commons/configuration/tree/ConfigurationNode.html">ConfigurationNode</a> nd = node;
<a class="jxr_linenumber" name="288" href="#288">288</a>             <strong class="jxr_keyword">while</strong> (nd != top)
<a class="jxr_linenumber" name="289" href="#289">289</a>             {
<a class="jxr_linenumber" name="290" href="#290">290</a>                 lstPathToRoot.add(nd);
<a class="jxr_linenumber" name="291" href="#291">291</a>                 nd = nd.getParentNode();
<a class="jxr_linenumber" name="292" href="#292">292</a>             }
<a class="jxr_linenumber" name="293" href="#293">293</a> 
<a class="jxr_linenumber" name="294" href="#294">294</a>             <em class="jxr_comment">// construct the keys for the nodes on this path</em>
<a class="jxr_linenumber" name="295" href="#295">295</a>             Collections.reverse(lstPathToRoot);
<a class="jxr_linenumber" name="296" href="#296">296</a>             String key = getSubnodeKey();
<a class="jxr_linenumber" name="297" href="#297">297</a>             <strong class="jxr_keyword">for</strong> (ConfigurationNode pathNode : lstPathToRoot)
<a class="jxr_linenumber" name="298" href="#298">298</a>             {
<a class="jxr_linenumber" name="299" href="#299">299</a>                 key = getParent().getExpressionEngine().nodeKey(pathNode, key);
<a class="jxr_linenumber" name="300" href="#300">300</a>             }
<a class="jxr_linenumber" name="301" href="#301">301</a>             result.setSubnodeKey(key);
<a class="jxr_linenumber" name="302" href="#302">302</a>         }
<a class="jxr_linenumber" name="303" href="#303">303</a> 
<a class="jxr_linenumber" name="304" href="#304">304</a>         <strong class="jxr_keyword">return</strong> result;
<a class="jxr_linenumber" name="305" href="#305">305</a>     }
<a class="jxr_linenumber" name="306" href="#306">306</a> 
<a class="jxr_linenumber" name="307" href="#307">307</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="308" href="#308">308</a> <em class="jxr_javadoccomment">     * Creates a new node. This task is delegated to the parent.</em>
<a class="jxr_linenumber" name="309" href="#309">309</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="310" href="#310">310</a> <em class="jxr_javadoccomment">     * @param name the node's name</em>
<a class="jxr_linenumber" name="311" href="#311">311</a> <em class="jxr_javadoccomment">     * @return the new node</em>
<a class="jxr_linenumber" name="312" href="#312">312</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="313" href="#313">313</a>     @Override
<a class="jxr_linenumber" name="314" href="#314">314</a>     <strong class="jxr_keyword">protected</strong> <a href="../../../../org/apache/commons/configuration/HierarchicalConfiguration.html">Node</a> createNode(String name)
<a class="jxr_linenumber" name="315" href="#315">315</a>     {
<a class="jxr_linenumber" name="316" href="#316">316</a>         <strong class="jxr_keyword">return</strong> getParent().createNode(name);
<a class="jxr_linenumber" name="317" href="#317">317</a>     }
<a class="jxr_linenumber" name="318" href="#318">318</a> 
<a class="jxr_linenumber" name="319" href="#319">319</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="320" href="#320">320</a> <em class="jxr_javadoccomment">     * Initializes this subnode configuration from the given parent</em>
<a class="jxr_linenumber" name="321" href="#321">321</a> <em class="jxr_javadoccomment">     * configuration. This method is called by the constructor. It will copy</em>
<a class="jxr_linenumber" name="322" href="#322">322</a> <em class="jxr_javadoccomment">     * many settings from the parent.</em>
<a class="jxr_linenumber" name="323" href="#323">323</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="324" href="#324">324</a> <em class="jxr_javadoccomment">     * @param parentConfig the parent configuration</em>
<a class="jxr_linenumber" name="325" href="#325">325</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="326" href="#326">326</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">void</strong> initFromParent(<a href="../../../../org/apache/commons/configuration/HierarchicalConfiguration.html">HierarchicalConfiguration</a> parentConfig)
<a class="jxr_linenumber" name="327" href="#327">327</a>     {
<a class="jxr_linenumber" name="328" href="#328">328</a>         setExpressionEngine(parentConfig.getExpressionEngine());
<a class="jxr_linenumber" name="329" href="#329">329</a>         setListDelimiter(parentConfig.getListDelimiter());
<a class="jxr_linenumber" name="330" href="#330">330</a>         setDelimiterParsingDisabled(parentConfig.isDelimiterParsingDisabled());
<a class="jxr_linenumber" name="331" href="#331">331</a>         setThrowExceptionOnMissing(parentConfig.isThrowExceptionOnMissing());
<a class="jxr_linenumber" name="332" href="#332">332</a>     }
<a class="jxr_linenumber" name="333" href="#333">333</a> 
<a class="jxr_linenumber" name="334" href="#334">334</a>     <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="335" href="#335">335</a> <em class="jxr_javadoccomment">     * Creates a ConfigurationInterpolator with a chain to the parent's</em>
<a class="jxr_linenumber" name="336" href="#336">336</a> <em class="jxr_javadoccomment">     * interpolator.</em>
<a class="jxr_linenumber" name="337" href="#337">337</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="338" href="#338">338</a> <em class="jxr_javadoccomment">     * @return the new interpolator</em>
<a class="jxr_linenumber" name="339" href="#339">339</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="340" href="#340">340</a>     @Override
<a class="jxr_linenumber" name="341" href="#341">341</a>     <strong class="jxr_keyword">protected</strong> <a href="../../../../org/apache/commons/configuration/interpol/ConfigurationInterpolator.html">ConfigurationInterpolator</a> createInterpolator()
<a class="jxr_linenumber" name="342" href="#342">342</a>     {
<a class="jxr_linenumber" name="343" href="#343">343</a>         <a href="../../../../org/apache/commons/configuration/interpol/ConfigurationInterpolator.html">ConfigurationInterpolator</a> interpolator = <strong class="jxr_keyword">super</strong>.createInterpolator();
<a class="jxr_linenumber" name="344" href="#344">344</a>         interpolator.setParentInterpolator(getParent().getInterpolator());
<a class="jxr_linenumber" name="345" href="#345">345</a>         <strong class="jxr_keyword">return</strong> interpolator;
<a class="jxr_linenumber" name="346" href="#346">346</a>     }
<a class="jxr_linenumber" name="347" href="#347">347</a> }
</pre>
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